Browsing by Subject "Coastal compound flooding"
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Item Near real-time coastal flood mapping(2022-05-16) Wang, Mark K.; Passalacqua, PaolaThe Texas Gulf Coast region contains significant centers of population, infrastructure, and economy, and is threatened by intensifying tropical cyclones. The resultant coastal flooding from cyclones such as Harvey and other extreme weather events often has multiple compounding drivers. This presents a complex numerical problem where a simulation must consider multiple hydrologic forcings. While there are several procedures for tacking this problem numerically, they tend to be resource-intensive and cannot be conducted in near real-time. We extend GeoFlood, a reduced physics conceptual framework for riverine flood forecasting, to rapidly predict storm surge and compound riverine-storm surge inundation. By modifying the Height Above Nearest Drainage (HAND) method for coastal environments we can map storm surge inundation on a 2.2 GB Digital Elevation Model (several counties at 10m x 10m resolution) in under 30 seconds on a personal computer with 64 GB of RAM. This method is validated against a numerical ocean circulation model (ADCIRC) simulation of Hurricane Ike, a major storm surge event on the Texas Gulf Coast. Despite the ADCIRC simulation's numerical solution and its consideration of weather forcings, the inundation map generated by the coastal HAND method is shown to have reasonable agreement at a fraction of the computation time. While our new model correctly predicts 99% of ADCIRC's inundated DEM cells, it also overpredicts inundated area by a factor of about 27%. We then combine this coastal HAND method with the classic GeoFlood framework for riverine flood forecasting to create a compound fluvial-storm surge inundation mapping workflow capable of being run in near real-time. This new coastal HAND method's fast wall-clock time and low CPU requirements can support decision making by first response personnel. The method provides timely and convenient access to crucial and high-resolution information such as the locations of flooded roads and buildings.